Demonstration of Power Improvements on a Diesel Engine Operating on Multiple Fuels

Continually increasing the maximum specific power output of engines used in military vehicles is vital to maintaining a battlefield advantage. An enabling technology for power optimization on existing engine architectures is advanced engine control based on real-time feedback control of the combustion. An engine equipped with intelligent controls and multi-fuel capable components has been used to demonstrate power improvements based on feedback control of the fueling by means of in-cylinder pressure measurements. In addition to optimized power output for the engine, the technology suite provides the capability to utilize both standard diesel fuel and alternatives such as jet fuel, biodiesel, or any mixture. A cylinder-balancing algorithm adjusts the fueling to achieve even power distribution between cylinders for improved performance and durability, or to operate all cylinders at the cylinder pressure limit when maximum power is required. Tests performed at lug-line conditions show that closed-loop control reduced the cylinder-to-cylinder Indicated Mean Effective Pressure (IMEP) variation from ±8% to ≺ ±2%. A multi-fuel algorithm adjusts and balances the cylinders to achieve optimal power output even when the fuel chemistry differs from standard diesel fuel, such as when operating on JP-8. This study quantitatively demonstrates that the normalized engine torque can be held within 2% for closed-loop operation between DF-2, JET-A and B100 fuels. The results of this work show improved power density of a diesel engine, with a wide range of fuels, through the combination of flexible, high pressure fuel injection technology and advanced engine controls with cylinder pressure feedback.